Method of producing solid carbon dioxide



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F. E. GILMORE mum Filed Nov. 21, 1931 kwrm.

METHOD OF PRODUCING SOLIVD CARBON DIOXIDE Jv dv Oct. 8,' 1935.

INVENTOR Forrest E. Gilmore A'TORNE Oct. 8, 1935. |=.|a.` MoRl-:V

METHOD OF PRODUCING SOLID CARBON DIOXIDE f Filed Nov. 21, 1951 2 Sheets-Sheet 2 'INVENToR" y Forrest E. Gilmare ArroRNEYs `Patented Oct. 8, 1,935

l 2,016,815 t ,t

METHOD F PRODUCING SOLID CARBON DIOXIDE -v frorrest E.Gi1more',"rulsa.or1a.

v Application November 1, 1931, Serial No. 576,475

12 Claims. (Cl. (VS2- 121) This invention relates to the production of carbon dioxide in relativelypure form. f An object of the present invention is'to produce carbondioxide bydir'ect combustion of'carbo- 5 naceous materials in relatively pure form.

Another object is to produce carbon dioxide by the combustion of carbonaceous materials in an oxygen containing atmosphere in which nitrogen is excluded. J Y.

A further object isy the production of carbon dioxide of substantial purity without'V the necessity of. absorbing such carbon dioxidek from a dilute mixture thereof and regenerating from the absorbent. s Another object is the combustion of such carbonaceous materials in an atmosphere containing oxygen mixed with carbon dioxide. l

Carbon dioxide rmay be produced lby the combustion of carbonaceousmaterials, which yields the` carbon dioxide mixed with 'a 'very vlarge amount of nitrogen and some oxygen. This necessitates absorbing the carbon dioxide in some way, usually by means ofralkaline carbonate solution and subsequentlyregenerating itfromfthis solution. This or other methods of purication v are costly and relatively diflicult. Y i

Itis quite impossible to obtain economically liquid carbon dioxide by direct compression cfa. flue gas resulting from the burningl of a carbonaceous fuel with air. y With the liquid receiver operating at a pressure of 4000 pounds to the square inch, no condensation of carbon dioxide will occur with ordinary cooling water temperatures. With pressure of` 2000 pounds and independent refrigeration ofthe liquid'receiver to a `temperature of minus 40- F. only abouttwothirds of the carbon dioxide is liquefied and the whole body of material must be brought to this high pressure and low temperature, the power requirement being prohibitive from-an economical pointof view.l Even if `by adesign of the apparatus the power requirements could be lessened,

it would still be impossible to recover the unliqueed third Vof the carbon dioxide by any subsequent procedurethat did not entail absorption.

It isvimpracticable toburn carbonaceous materials with pure oxygen on account of the very high temperatures that are reached by combustion under such circumstances andthe consequent serious eifect -on the apparatus used. In-particular, it is not feasible to use this method inthe burning of a carbonaceous fuel in an internal combustion engine both becausey of the explosive nature of the reaction and because a'body of indifferent gas is necessary. in order to develop the mechanical energy for operating the engine from the'combustion.;4

.VI accordinglyprovide an artificial atmosphere consisting of amixture of pure oxygen and carbon dioxide and by the jusecfA this atmosphere '5 I am able to secureav combustion of the carbonaceous fuel either in a furnace or in an internal combustion engine without producing unmanageably high temperatures and am able in this way to obtain gases `of combustion which arefsubl0 stantially entirely carbon dioxide mixed with water vapor. v s v s The carbonaceous materials used may be either coal, coke, or fuel oil, `or combustible gas such as' natural gas. In the'ctse` of the two latter 15 materials, combustion may be carried 'out either in a furnace or in a Diesel or other type of internal combustion engine. In either case, the' fuel is burned in an atmospherev consisting substantially of carbon dioxide to which has been added the 20.'

desired amount of pure oxygen, the latter being obtained from any desired source. However, fthe v combustion of the carbcnaceous fuel is carried out, itA vvillbe'l desirable to obtain asfar as possible the available mechanical energy 2U from it in order to drive thenecessary apparatus. Inthe case of combustion ina furnace, it will be desirable that the furnace heat a boiler both to obtain steam to drive the necessary apparatus and torcool the gases of combustion.' In the case of 3U an internal ycombustion engine, the mechanical energywill, ofcourse, be' obtained'directly. e Referring now to the drawings in which like numerals referto like parts:

of carbon dioxide in solid form using a furnace and boiler; and y n A Fig. 2 showsdiagrammatically a similar apparatus in which an internal combustion engine is used for combustion. i 40 Referring to `Fig. l, a suitable furnace is shown, consisting of a fire pit {,boiler 2, firetubes 3 and stack l. A flue 5 connects with the stack 4 above the furnace to receive'and return a portion of the gases of combustion to the re pit I, there 45 being provided a blower 6 to cause recirculation ofthe flue gasesnin this way. Above the connection between the ilue 5 and thev stack'l is provided a valve or damper` means l2 which, when closed. will prevent gases from going ug. the stack and cause them to be entirely diverted to the tlue 5. v

v v'Ihe fire pit I is provided with the oil burner I9 in this embodiment, although if solid fuel is used a grate may be substituted, preferably with mechanical stoking which will be substantially gas tight. The fire pit is provided with the air port II in which is the gas tight valve 5, for purposes of starting. In the course of the return flue 5 is an orifice 45, the flue on either side of this orifice being connected with the ratio controlled device 44 by piping transmitting the pressure on either side to the diierential mechanism thereof.

Communicating with the portion 1 of the flue 5 between the ratio controller orice 45 and the nre pit I, is a pipe 5 supplying pure oxygen. In the pipe 5 is the orifice 45, pressure connection being made from either side of the orlilce 45 to the ratio controller .44. The ratio controller 44 controls the valve 41 in line 5, and in this. way any predetermined addition of oxygen can be made to the iiue gases passing through the return flue 5 to secure the desired conditions for combustion as regards excess or deficiency of oxygen, depending on the use to which the carbon dioxide is to be put. A pipe I0, to which is attached the venting rvalve 51, leads from the due `5 to carry away the carbon dioxide produced, and communicates with the water cooler I3, provided with water inlet 42 and .outlet with trap 45, a pipe 59 connecting this with the chemical dryer I4. The dryer I4 communicates by the pipe 33 with the cylinder 39 of the compressor 25.

The compressor 25 may be conveniently driven by steam, steam being provided by the boiler 2 through the pipe 52. The gas from the low pressure cylinder passes to the low pressure intercooler 4I and high pressure cylinder 45. The highly compressed hot gas passes from the high pressure cylinder to the cooling coils 21 where itis substantially liquefied, except for the excess oxygen gas. It now passes to the liquid receiver 53. from the bottom of which a pipe 54 leads the liqueed carbon dioxide to the heat exchanger 3 I Here it is further cooled, and then passes through the expansion valve 32 to the nozzle'25 inside of the freezing chamber 25.' The freezing chamber is heavily insulated with the insulation 34. Passing from thetop of the freezing chamber. is the return 'duct 35 leading to the other side'of the heat exchanger 3I and from this the gas which has been warmed up prac-l tically to room temperature is lead by the pipe 35 to-join the pipe 33 leading to the inlet of the compressor 25. I'he gas accumulating in the top of the liquid receiver 53 is lead of! by the pipe 55 in which is the throttling valve 55. As this gas under high pressure is reduced by this valve 55 practically to normal pressure some refrigerating effect is secured and this effect may be conveniently used to cool the liquid in receiver 53, although not so shown. v By the pipe 55, this gas, which is in part carbon dioxide and in part oxygen, is returned to the portion 1 of return ue 5. By proper adjustment ofthe pressure on receiver 53 with respect to the percentage of excess oxygen in the compressed gas, the issuing gas from pipe 55 may be made to have the desired proportion between oxygen and carbon dioxide. Forl example, if there is threepercent of excess oxygen by volume in the gas to'be compressed, and the gas is compressed to a pressure which is once and a quarter that of the vapor pressure of carbon dioxide at ythe temperature at which the receiver 53 is maintained, the

gas passing from the top of the receiver will be 20% by volume oxygen. l

Any fuel desiredis burned in the fire pit I, either on a grate inl the case of solid fuel orby means of the burner if fluid fuels are used.

Combustion being started with the air port II, damper I2, and venting valve 51 being open, the blower 5 is started and pure oxygen is supplied through the pipe l. The air port II and the damper I2 are now closed. 5

At this moment the gas issuing from the venting valve 51 is an ordinary flue gas consisting largely of nitrogen. Since, however, no nitrogen is added to the system, the gas passing from venting valve 51 becomes poorer and poorer in 10 l nitrogen and it finally becomeapractically pure carbon dioxide containing a little excess oxygen and water vapor. If the proportion of carbon to hydrogen is high in the type of fuel used there will be produced Inearly a volume of new carbon 15 dioxide for every volume of oxygen that is supplied from the pipe 5. Venting valve 51 is now closed, the compressor 25 is started and the gas owing in pipe, I0 passes through the water cooler and chemical dryer I3 and I4. Here the 20 water vapor is substantially removed. The carbon dioxide gas containing a little excess oxygen is then compressed in the compressor 25.

It passes first to the lowpressure cylinder 35 of the compressor 25, is cooled by the intercooler 25 4I and is then further compressed in the high pressure cylinder 40 of the compressor 25. It is then cooled substantially to room temperature in the cooling coils21.v

The largest portion of the carbon dioxide is 30 liquefied, the amount unliquefled depending upon the amount of excess orwgen and the ratio of the pressure in the receiver 53 to the vapor pressure of carbon dioxide at the temperature ofthe receiver as above noted. I I

The liquid carbon dioxide now passes through the heat exchanger 3i where it is cooled by the cool carbon dioxide returning from the freezing chamber 25 and then passes through the expansion valve 32 and the spray nozzle 25 into the o freezing chamber 25. This chamber is malntained substantially at; atmospheric pressure in order to produce solid carbon dioxide at a temperature at which its evaporation pressure is not greater than that of the atmosphere. The liquid 45 carbon dioxide pasing into this chamber is partially frozen and partially vaporized. 'Ihe vaporized carbon dioxide is returned by the pipe 35 to the inlet of the compressor 25, first, however, passing throughthe heat exchanger 3l where it 50 isbrought practically to room temperature, and in so doing cools the liquid carbon dioxide passing to the freezing chamber.

'I'he carbon'dioxide snow falls to the bottom of the spray 'chamber where it is compressed by 55 the snow press 35 to form blocks, which are collected inthe storage chamber 31. This storage chamber 31 v and the freezing Y chamber 25 are heavily insulated, and the storage chamber 31 is also kept relatively gas-tight so that the evaporated carbon dioxidev can be returned through pipe 35 back into the system. In this way waste of carbon dioxide through evaporation in the storage chamber is avoided. While not so shown, an air lock may be provided at the door of this chamber to prevent contamination of the atmosphere within the chamber with atmospheric air while the carbon dioxide blocks are being removed.

Referring now to Fig. 2, there is shwn diagrammatically the method of burning a fluid fuel in an internal combustion engine,fpreferably of the Diesel type. In this figure, I5 is the cylinder of an internal combustion engine 5I having the inlet ports I5, outlet ports I1, these ports being can be supplied to the cylinder' I5. 'Ihe mixture issuitablyY proportioned by thev ratio controller 58, with orifice 51 inpipe I8, orifice 58 in oxygen pipe `I8 andcontrol valve 59v-in the latter. This mixture is highly-compressed in the cylinder I5 and fuel oil is suppli'edby-the pipe^20 tothe in,-

jecting mechanism 2| and by thi'sfto the cyl.- inder. The yfuel is f thereby burned 1 in -the -usual Diesel c'ycleand the engineis thereby driven, serving'fto drive the compressor 55.1.The exhaust gas passes from the port I1 by pipe 69 to thecooler 22, Vwherethe'v gasis cooled and then passes throughv the pipe 68 inwhichis the venting valve 51, tothe water scrubber 23 provided with water inletBI and outlet trap 88. Here the water vapor is largely removed. The l.gas thenpasses by the pipe 1I to the chemical drier 24 where it is practically wholly dried.-v This connects by Vthe .pipe vwiththe low pressure'cylinder--52 of the compressor 55.-, From here it 'passes to the inter,-

cooler 53 'andfthen'to the high .pressure cylinder 54. The latter connects with the cooling coils 21 and from there on the apparatusfis similar'to that in- EFig. l,V` and 'carries -lilrev reference numerals.

The return pipe 35, however, for the excess carbon dioxide vin this case joins thepipe. 25 kleading to the inletof the `coinpre`ssor=55insteadof pipe 33,' as inFig. 1,and thepipe 65 vconnects.with'jthe rOperation is essentiallysimilar in principle'to the operation' in the case of the apparatus shown in Fig. 1. With the valve 10 turned to supply air to the cylinder I5, with the valve 51 in the pipe 58 open, with the valve 13 in pipe 59 open, and with the clutch 12 between the Diesel engine 5I and the compressor 55 open the engine 5I is started. When running smoothly, the three-way valve 10 is turned so that the cylinder I5 will take its supply of gas from the pipe I8, and the valve 13 in the pipe 59 is closed, the valve 51 still remaining open. Circulation commences in pipe I8 and oxygen is supplied from pipe I9, the excess volume being vented at 51. 'I'he issuing gas soon becomes, as before, practically pure carbon dioxide. 'I'he clutch 12 is now thrown in, starting the compressor'- 55 and the venting valve 61 is closed. The gas, as before, is liqueed and accumulates in the receiver 53,I the excess oxygen and a certain amount of unliquefied carbon dioxide passing back'to the pipe I8, and then to the cylinder I5 where it is used in the combustion of more fuel. The liquefied carbon dioxide is expanded in the freezing chamber 29, a portion being solidified and a portion returning by the pipe again to the compressor 55, to again pass through the liquefying cycle.

It will thus be seen that `I have devised a method for the direct production, by combustion, of carbon dioxide gas of relatively high purity, the purity being so high that itcan be used dlrectly for liqueflcation or solidiflcation without i further treatment.

It will also be seen that Ihave devised a method in which substantiallyall of the carbon dioxide produced is eventually recovered. It will also be seen that I have devised a method whereby the power 'obtained in the burning of a carbonaceous fuel will be-sufllcient to obtain the carbon dioxide resulting from that fuel in the form of solid carbon dioxide, and it will be observed that this con- `out departing from my invention as defined in the stitutes a very economical process for the production of solid carbon dioxide.

,- Furthermore, 4it, is tombe ,understood `that the particular form of apparatus 'shown and described, andthe particular procedureset forth, 5

areA presented for purposes of explanation and illustration and that ,various 4modifications of said apparatus and procedure can be made withappended claims. n 10 What I claim ist. .i ,u l.. The process of; p'lOduclng carbon dioxide gas, which consistsvin preparing a mixturesof substantially pure carbon .dioxideand substantially pure oxygen, burninga fluidfcarbonaceous fuel in such 15 artificial atmosphere in the combustion chamber of*- an internal `combustion engine removing the water vapor from the exhaust gases and recover.-

ing carbon, dioxide from said 'exhaust' gases.

2. The process `of producing carbon dioxide, 20

.which Yconsists in preparing an artificial 'atmosphere composed of substantiallypure carbon dioxidey and substantiallypure oxygen, mixing such an atmosphere with a fluid Aca rbonaceous fuel in suitableA proportions 'for' combustion, introducing 25 such mixture into the'combustion chamber of an internal combustion engine, burning the mixture removingA the water vaporfrom the exhaust gasesand recovering carbon dioxide therefrom.

3.-Thef"process1of producing carbon dioxide, 30 which consists infp'reparing an artificial atmosphere comprising substantiallyf'pure carbon-dioxide A andsubstantially pure oxygen, introducing such mixture "into, they combustion chamber y ,oIE an internal combustion engine, highly compressing 35 said mixture, Vintroducing fa, liquid carbonaceous fuel into said combustion chamber, burning the same and recovering carbon dioxide from the products of combustion.

4. In an apparatus for the production of car- 40 bon dioxide, a combustion chamber enclosing a combustion zone, means for supplying carbonaceous fuel to said combustion chamber, means for mixing a portion of the gases of combustion with oxygen, and means for supplying said mixture to said'combustion zone in said combustion chamber. Y

5. In an apparatus for the production of relatively pure carbon dioxide, a combustion chamb ber enclosing a combustion zone, means for supthereof, means for compressing the dried gases,

means for cooling and condensing a portion of said compressed gases, and means for returning the uncondensed gases to said combustion zone.

6. In an apparatus for the production of relatively pure carbon dioxide, in combination, -a combustion chamber, a boiler heated by said combustion chamber, a compressor, a steam engine receiving steam from said boiler for driving such compressor and receiving steam `from the boiler, a source of substantially pure oxygen gas, pipe connection between said source of oxygen f and said combustion chamber, a return flue carrying gases of combustion back to the combustion chamber, means for y proportionately 7o mixingsaid oxygen and said combustion gases,

a4 washing scrubber for said combustion gases,

a dryer for'said combustion gases, means for carrying a portion of the combustion gases from said dryer to said compressor, cooling means for the compressed gases, whereby partial liquefaction of carbon dioxide occurs, a receiver receiving the liquid carbon dioxide and the unliqueiled gases and means connected to the top of said receiver i'or conveying said `unliquened gases to said combustion chamber. f

'7. The process otproducing solid carbon dioxide gas, which comprises, burning a carbonaceous fuel in an atmosphere composed essentially of carbon dioxide and pure oxygen in the combustion chamber o! an internal combustion engine, the oxygen being in excess, Aremoving the water vapor from the exhaust gases from said engine, highly compressingvsaid gases, cooling said gases whereby iiquefaction of most of the carbon dioxide occurs. passing said mixed liquid and unliquefled gases to a liquid receiver, removing `the liquid from said receiver, bringing said liquid substantially to atmospheric' pressure whereby a portion thereof `is frozen and a portion is vaporized, returning theunliqueiied gases from the liquid receiver to the cylinder of the internal combustion engine to assistin iurther combustion andr returning the vaporized liquid carbon dioxide to the cylindersof the compressor. l j y 8.The process of producing relatively pure carbon dioxide, which consists in preparing an atmosphere consisting substantially. of oxygen and carbon dioxide, burning a carbonaceous fuel containing hydrogen in said atmosphere, .removing the watervapor from the product o! combustion. compressing and coolingthe resulting gas whereby the carbon dioxide is largely-liquefied, and returning the unliqueiied gas to assist in burning more .carbonaceous fuel.

9. The process of producing relatively pure carbon dioxide, which consists in preparing an atmosphere composedv substantially of oxygen and carbon dioxide, burning a carbonaceous fuel in said atmosphere the oxygen being present in excess, compressing and coolingv the resulting gaswhereby the carbon dioxide is largely liquefled, returning the unliqueiled portion comprising the excess oxygen and some unliqueed carbon dioxide to assist in supporting 'further combustion.

10.-The. processpf producing carbon dioxide gas which consists in preparing a mixture of substantially pure carbon dioxide` and substantially pure oxygen, burninga ,fluid carbonaceous fuel in such artificial atmosphere in the combustion chamber of an internal combustion .engine and recoveringv carbon :dioxide from the exhaust gases.

1l. They process of prod ucing carbon dioxide gas which comprises preparing an atmosphere composed substantially of oxygen and carbon dioxide and burning a carbonaceous material in said atmosphere. v v

l2. The process of producing carbon dioxide gas having as ,its principal gaseous impurity, oxygen, which comprises preparing an atmosphere composed substantially of oxygen and carbon dioxide, burning a carbonaceous material `containing hydrogen in said atmosphere and removing water vapor from the products of combustion. f s

FORREST E. GILMORE. 

